This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. Section 119 from an application for HOME ZONE SERVICE METHOD FOR MOBILE TELEPHONE SUBSCRIBERS IN MOBILE RADIO COMMUNICATION SYSTEM filed earlier in the Korean Industrial Property Office on Jul. 5, 1999 and there duly assigned Ser. No. 26956/1999.
1. Field of the Invention
The present invention relates to a home zone service for a portable mobile telephone subscriber within a mobile telecommunication network. More particularly, the present invention relates to a method for improving accuracy and performance in providing a home zone service.
2. Description of the Related Art
A home zone service is known as allocating a predefined zone, known as xe2x80x9chome zonexe2x80x9d, so that a different charging rate can be applied to a mobile telephone subscriber, depending on whether the subscriber is located within the home zone when placing a call. Thus, a mobile subscriber can selectively designate a number of different home zones at a given time as the mobile subscriber moves from one geographic location to another geographic location.
If the vicinity of a subscriber""s residential area were defined as the home zone service area, a service charge equivalent to a local wired telephone service can be applied to a mobile phone subscriber. But, if a call is made outside of the home zone, a higher charging rate corresponding to a radio telephone call rate is applied to the subscriber.
If a subscriber requests a home zone service, the boundary of the home zone is determined according to various factors, such as the position (latitude/longitude) of the base station with respect to the subscriber""s address, the base station coverage area, the installation conditions of the base station, the multi-path characteristics of the base station area, etc.
With reference to FIG. 1, a cell site is divided into a plurality of sectors. Accordingly, a home zone can be defined to include the whole cell area (base station) or one of the sectors. In determining the home zone, however, the accuracy of home zone recognition is important to the service providers in terms of the amount of revenue they can generate. A minor error in determining the home zone boundary, causing the widening of the home zone boundary, can cost a significant revenue loss to the service providers. Thus, the ability to accurately recognize the home zone boundary when a subscriber originates (or terminates) a call within the home zone is important in boosting revenue for service providers.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a home zone service method which can perform a more accurate way of determining whether a mobile subscriber is located within the home zone service when making a call connection.
In order to achieve the above object, according to the present invention, there is provided a home zone service method for associating a predetermined zone to a mobile telephone subscriber and charging the subscriber at different billing rates based on whether the subscriber makes a telephone call inside or outside the home zone. The method includes the steps of: associating a plurality of reduced charging areas with a mobile subscriber, wherein the boundary of reduced charging area is defined as a first measurement value and a second measurement value, and wherein the first value and the second value are measured based on a mean round trip delay from a plurality of locations within the sector of a cell site to which the subscriber is located in relation to the neighboring base stations, then preparing a home zone database including the measured first value and the second value; calculating a round trip delay of a request signal of the mobile subscriber to establish a call connection; and, determining whether the subscriber is inside the home zone if the calculated round trip delay falls between the first value and the second value retrieved from the home zone database.
According to one aspect of the present invention, if the mobile phone is located within the home zone, the subscriber is informed of whether he/she is located within the home zone.
According to another aspect of the present invention, the predetermined home zone data base is stored and retrieved from a data base management center.